A final drive of the above-mentioned kind is customary on rear-wheel driven road vehicles—cars. The trend nowadays, however, is towards all wheel drive (AWD) cars. In such a car, a front wheel drive can be supplemented with an intermediate axle, an AWD coupling, and a final drive for driving also the rear wheels.
When a car is to be provided with an AWD coupling, it is presently customary that the AWD coupling and the final drive (including the differential) are supplied from different sources. The design is often such that an AWD coupling/final drive-unit is formed in that the housing of the AWD coupling is physically attached to the housing of the final drive, the disc drum or similar means being connected to the pinion axle.
The supplier of the final drive thus provides the proper journaling therefore.
As is well known in the art, the journaling of the pinion axle in the final drive is rather intricate, because a certain pre-stress has to be provided, especially if the pinion gear/crown gear set is a hypoid gear set. The pinion axle is thus normally journaled by two conical roller bearings or angular contact bearings, which are prestressed by a nut arrangement to be manually tightened to the correct prestress value.
The rotatable parts of the AWD coupling are likewise to be separately journaled in the coupling housing (although one of the bearings may be provided between the ingoing axle of the coupling and the pinion axle).
Generally speaking, the provision of the final drive and the AWD coupling as in principle two separate, “self-contained” (but connected) units means high cost, weight, space requirement, and losses.
The main object of the invention is to remove this and other disadvantages with the present design.